Type of Gears - Herringbone Gears

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A herringbone gear, also known as a double helical gear, is a gear that combines two helical gears of opposite hands, placed side-by-side. The teeth are arranged in a "V" shape, resembling the bones of a fish. This unique design allows it to transmit power smoothly and with less noise than other types of gears.

Key features and advantages:

Neutralized axial thrust: A key feature of herringbone gears is that the opposing axial thrust forces from each helical half cancel each other out. This eliminates the need for large, costly thrust bearings, which are necessary for single helical gears. High load capacity: With a larger contact area due to multiple teeth meshing at once, herringbone gears can distribute the workload more evenly. This allows them to handle significantly higher loads and torque than spur gears. Smooth and quiet operation: The gradual engagement of the angled teeth results in smooth power transmission with reduced vibration and noise, making them ideal for high-speed applications where quiet operation is critical. Improved lubrication: The V-shape of the teeth helps promote better oil flow, which ensures more effective lubrication between the gear surfaces. Strength and reliability: The design's strength and stability make herringbone gears particularly well-suited for demanding, heavy-duty applications.

Disadvantages

Manufacturing complexity: Herringbone gears are difficult and expensive to manufacture, as standard gear hobbing machines cannot be used due to the continuous V-shape of the teeth. Specialized processes: They require slower and more specialized processes like gear shaping. Assembly issues: When assembled from two separate helical gears, errors can occur during joining, which reduces the efficiency and optimal contact pattern. Lower accuracy: Because of the complex manufacturing and assembly, herringbone gears can have lower accuracy, particularly in comparison to gears with simpler designs. Bulkier design: The manufacturing process often requires a central groove or a wider face width, making the gears physically wider than single-helical gears, which can be a problem for space-constrained applications like automotive transmissions. Lower efficiency: While they eliminate axial thrust, assembly errors can sometimes lead to lower overall efficiency compared to an ideal gear. Not ideal for all applications: Due to their complexity, they are not as productive and are often limited to applications where their unique benefits, such as zero axial thrust, are most needed, like heavy machinery.